"The United States appreciates the willingness of the government of Oman and other partners to support ongoing US efforts focused on responsibly reducing the detainee population and ultimately closing the Guantanamo Bay facility," the Defense Department said in a statement.

With the announcement of the 11 Yemenis' release -- which came a week after the Defense Department said it had repatriated another detainee to Tunisia -- 15 remain at Guantanamo, down from a peak of nearly 800.

Of them three are eligible for transfer, three are eligible for a review for possible release, seven are facing charges and two have been convicted and sentenced, the Defense Department said.

Outgoing President Joe Biden pledged before his election in 2020 to try to shut down Guantanamo, but it remains open with just weeks left in his term.

The facility was opened in the wake of the September 11, 2001 attacks and has been used to indefinitely hold detainees seized during the wars and other operations that followed.

The conditions at Guantanamo Bay have prompted consistent outcry from rights groups, and UN experts have condemned it as a site of "unparalleled notoriety."